Conventional hydraulic cylinders are composed of a cylindrical housing that contains within the housing a piston which moves axially therein. Mounted on or connected to the piston is a piston rod that extends through the end of the cylindrical housing along the axis thereof to a remote or free end. The opposite end of the rod extends through the piston and is threaded. The threaded end receives a nut which tightens against the piston for holding the piston on the rod. The remote or free end normally has a connecting structure thereon that utilizes a pin extending radially with respect to the axis of the rod and which connects the rod to a unit or member that utilizes the power of the hydraulic cylinder.
One of the problems relating to large hydraulic cylinder assemblies of the type that is used, for example, on industrial equipment, is the servicing of the assembly and particularly the piston and the piston rod. Often, the piston will carry the piston rings and seals that, over a period of time, become worn. Consequently, it is necessary to remove entirely the total piston and piston rod from the cylinder. Normally, the piston is connected to the threaded end of the piston rod by a nut with a relatively large torque. This torque is of such magnitude that it is greater than that which may be done manually by a man turning the nut with a conventional type wrench. It is therefore necessary to provide power means for applying additional torque to the nut when it is being tightened against the piston or when it is being removed from the piston so that the rod and piston may be serviced.